Adding Illumination to your Model for Night Flight

 

One of the favorite aircraft for night flying is the Kadet Senior by SIG. There are several reasons that this particular model is so popular. First of all, it is a gentle flyer, considered a good trainer, and that's important when you begin your night flying career! You will have so many things going on as it is that you don't want to bothered with a difficult flyer. Second, this model can easily carry the additional weight of the lights, controller and battery pack.

Many modifications will be discussed in this article, so pick and choose the ones that appeal to you.

A quick word about wiring:

The Flite-Lite Controller used in this article has a 10 pin connector which wires all of the lights on the aircraft. In keeping with Standard Color Coding, the following Wire Colors are recommended and will be referred to throughout this article.

Pin 1 - BROWN (B-) - Battery Negative
Pin 2 - RED (B+) - Battery Positive
Pin 3 - ORANGE (L-) - Landing Lights Negative
Pin 4 - YELLOW (L+) - Landing Lights Positive
Pin 5 - GREEN (N-) - Navigation Lights Negative
Pin 6 - BLUE (N+) - Navigation Lights Positive
Pin 7 - VIOLET (S1-) - Strobe #1 Negative
Pin 8 - GRAY (S1+) - Strobe #1 Positive
Pin 9 - WHITE (S2-) - Strobe #2 Negative
Pin 10 - BLACK (S2+) - Strobe #2 Positive

Each pair (positive & negative) of wire should be twisted. AWG 22-26 Stranded is recommended.

 

THE WINGS:

CAUTION: The following modifications, and lighting battery can add considerable weight to your model. Use good judgment when choosing these options.

There are 3 very popular methods of dealing with the "LANDING LIGHTS" and numerous variations.

1 - single or dual cowl mounted
2 - under wing (hanging) mounting
3 - leading edge recessed

Before you start building, from some scrap material, cut and shape 4 half ribs. These will be used later for the landing lights.

I will describe the 3rd option, definitely the most difficult but probably the most impressive of the various methods. This requires removing a section of leading edge material between two ribs on each wing panel. The problem is to replace the structural integrity that is lost by severing the leading edge.

One method is to add another set of spars between the main spars and the leading edge. This will replace some of the tortional stability. Top and Bottom sheeting definitely helps, but beware of the weight increase. Prior to assembly, stack and drill a 1/4" hole through all of the ribs, or alternatively, if the wing is already built, you can use a single hole paper punch and pop a hole in each rib, just in front of the main spars, centered top & bottom. This hole will be used for routing the wires. Build the two wing halves according to the plans, but hold off on that sheeting. Add the two new spars. You might consider carrying the shear webs all the way to the wing tips for added strength.

This is the time to decide on Flaps and/or Ailerons. I use Barn Door type construction and mount 4 servos to control them. The technique is left to the modeler, there are many excellent articles available on this subject. 

  
Wing without Top Sheeting, Note additional spars, Wing Tip Light and Trailing Tip Strobe
Landing Light and Cutout for Flaps & Aileron w/ Servos

THE WING TIPS:

The Wing Tips require some thought about the mounting of the Navigation Lights. Basically I use a socketed light with a removable colored lens for easy bulb replacement. Check your local electronics supplier for a variety of lights. A good choice is a socket that uses the #328 miniature lamp. The socket should be positioned in line with the main spars and parallel to the top wing surface. Because of wing tip taper, a small wedge may be required to mount the socket. Keep the wedge as small as possible for aerodynamic reasons. It is important that the lens protrude beyond the wing tip so that the light can be seen in a shallow bank from the opposite side. Wire the Navigation Lights (N) using the GREEN/BLUE twisted pair.

Trailing Tip Strobes are implemented using the #328 miniature lamps with the VIOLET/GRAY twisted pair soldered directly to the lamp. Leave enough of a service loop so that the lamp can be replaced if necessary. I use a dab of Silicone to hold the lamp in place and you might consider a clear lens to complete the tip profile, or just the bare bulb sticking out of the tip.

 

Note: with the advances in technology, today I would be using super bright LED's for all the lights, resulting in a much smaller battery pack for the lights.

Wing Tip Viewed from Bottom Side of Wing

THE LANDING LIGHTS:

First you must decide which bay the landing lights will occupy. Mark the bay on BOTH wing halves so you don't wind up cutting the wrong bay. Join the two wing halves at this time. If you installed the Ailerons, then you should reduce the dihedral from 6" to 2-3". Use a good strong wing joiner here, remember you will be carrying extra weight. Install the Top Leading Edge Sheeting. This can be done by sanding a small portion of the rib at the leading edge. the remainder of the rib can stay full height. Install the sheeting so that it butts up against the Leading edge and overlaps the main spars. the ridge at the main spar can be sanded to a feathered edge, so that it won't show when you put the covering on. Next use some 1/8" light ply to make a shear web and fit it on the front side of the spars that you added. This needs to be a snug fit. Remove it and drill a 1/4" hole in each of the shear webs. Using a reamer, widen the holes until the Halogen HPR-51 bulbs or Super Bright LEDs fit snugly. Now go ahead and glue the two shear ribs in place. Next we want to double the inside of the bay with the Half Ribs you made earlier.

Now it is time to cut the leading edge. It should be cut flush with the inside of the light bay. Use a straight edge and notch the Top Sheeting back another 1/8", a clean straight line.

Next wire the Landing Lights using the ORANGE/YELLOW twisted pair. again be sure to leave a service loop so that the bulbs can be replaced if necessary. Secure with a dab of Silicone. Install the bottom sheeting and cutout all the way to the shear rib.

 
The last problem on the wing that we need to address is connecting all of these wires to the fuselage. I use a Molex #WWF-3906PRT (Waldom) connector that has 12 contacts. This will accommodate the 2 servo circuits (6 wires) and the 3 Light circuits (6 wires). If you crimp both wires (one from each wing halve), e.g. both yellow wires, into a single pin, then there is no need for "Y" cord adapters, the connection itself becomes the splice. I mount the chassis side of the connector in the bottom center section. Using some scrap, double the sheeting thickness in this area and epoxy the connector in place.

 
Install the remaining sheeting in the center section and the wing is now ready for final sanding and covering.

THE FUSELAGE:

On my model, this is where the whole meaning of Kit Bashing takes place. Tail Dragger, 30's Vintage Tail Feathers, and a fiberglass cowl totally change the appearance. On the fuse, I added some balsa stringers to get rid of the boxy look. A rotating Beacon is installed just behind the wing saddle. This is actually Strobe #2 and is wired with the WHITE/BLACK twisted pair. I used the same type light socket as the Navigation Lights. A jumper on the Flite-Lite controller changes the function from Strobe to Beacon. The Rudder Assembly has a White Taillight. This is wired in parallel with the Navigation Lights, so use the BLUE/GREEN twisted pair. I pass the wires through the hinge line. An alternative is to mount the Rotating Beacon at the Top of the Vertical Fin/Rudder.


Vertical Fin with Rotating Beacon and Tail Light